Peripheral neuropathy is a failure of the nerves that carry information to and from the brain and spinal cord. This produces pain, loss of sensation, and inability to control muscles.
In some cases, the failure of nerves that control blood vessels, intestines, and other organs results in abnormal blood pressure, digestion problems, and loss of other basic body processes. Peripheral neuropathy may involve damage to a single nerve or nerve group (mononeuropathy) or may affect multiple nerves (polyneuropathy).
There are numerous reasons for nerves to malfunction. In some cases, no cause can be identified. Damage to nerves can result from one of the specific conditions associated with neuropathy, including: (1) Hereditary disorders, such as Charcot-Marie-Tooth disease or Friedreich's ataxia; (2) Systemic or metabolic disorders, such as Diabetes (diabetic neuropathy), Dietary deficiencies (especially vitamin B-12), Excessive alcohol use (alcoholic neuropathy), Uremia (from kidney failure), or Cancer; (3) Infectious or inflammatory conditions, such as AIDS, Hepatitis, Colorado tick fever, diphtheria, Guillain-Barre syndrome, HIV infection without development of AIDS, leprosy, Lyme, polyarteritis nodosa, rheumatoid arthritis, sarcoidosis, Sjogren syndrome, syphilis, systemic lupus erythematosus, or Amyloid; (4) Exposure to toxic compounds, such as sniffing glue or other toxic compounds, nitrous oxide, industrial agents—especially solvents, heavy metals (lead, arsenic, mercury, etc.), or drugs; and (5) Miscellaneous causes, such as ischemia (decreased oxygen/decreased blood flow), or prolonged exposure to cold temperature.
Diabetic neuropathy is a nerve disorder caused by diabetes. Symptoms of neuropathy include numbness and sometimes pain in the hands, feet or legs. Nerve damage caused by diabetes can also lead to problems with internal organs such as the digestive tract, heart and sexual organs, causing indigestion, diarrhea or constipation, dizziness, bladder infections and impotence.
The cause of diabetic neuropathy remains undefined, but several factors are likely to contribute to the disorder. For example, high blood glucose causes chemical changes in the nerves that impair the nerves' ability to transmit signals.
Diabetic neuropathy can affect virtually every part of the body. Diffuse (peripheral) neuropathy affect the legs, feet, arms and hands. Diffuse (autonomic) neuropathy affects the heart, digestive system, sexual organs, urinary tract and sweat glands. Focal neuropathy affects the eyes, facial muscles, hearing, pelvis and lower back, thighs and abdomen.
Diabetic individuals are also prone to developing compression neuropathies. The most common form of compression neuropathy is carpal tunnel syndrome. Asymptomatic carpal tunnel syndrome occurs in 20-30% of diabetes sufferers whilst symptomatic carpal tunnel syndrome occurs in 6-11%. Numbness and tingling of the hand are the most common symptoms. Diabetic peripheral neuropathy is also a fundamental cause of a large proportion of diabetic foot ulcers. The lack of sensation caused by this condition results in the individual being unable to detect points of pressure that would normally cause low level pain and therefore behavior would be corrected to stop the pain (i.e., relieve pressure on that part of the foot). Without that sensation the insult continues and results in ulceration of the skin that can then become a chronic wound and in a significant number of cases results in amputation.
Other examples of neuropathies include chemotherapy-induced neuropathy, alcoholic neuropathy and HIV/AIDS neuropathy.
Regaining the sensation by stimulating nerve regeneration would therefore have a significant impact on the quality of life of those individuals suffering from peripheral neuropathy, particularly diabetic peripheral neuropathy.
The current goals of treating diabetic neuropathy are to prevent progression and reduce the symptoms of the disease. Tight control of glucose is important to prevent progression. To reduce the symptoms, topical treatment with Capsaicin or oral medication like amitriptyline, gabapentin, and carbamazepine have been used successfully. Analgesics (pain medications) may work for some patients on a short-term basis. But, in most cases, they usually do not provide much benefit.
The current protocols for treatment of neuropathies are limited to relieving pain and discomfort, as well as to preventing additional tissue damage. Therefore, there is a need in the art for a therapy which promotes nerve regeneration rather than treating the symptoms of the pathologies.